&#34;Chislett Summer Navel&#34; orange tree

ABSTRACT

A new and distinct variety of navel orange tree which is somewhat remotely similar to the &#34;Late Lane Navel&#34; orange tree with which it is most closely related but from which it is distinguished by producing fruit which are mature for harvesting and shipment in early September holding on the tree until the end of April at Kenley, Victoria, Australia and which produces a higher internal flesh and external rind quality and color than comparable varieties.

BACKGROUND OF THE NEW VARIETY

The present invention relates to a new and distinct variety of orangetree which will hereinafter be denominated varietally as "ChislettSummer Navel" orange tree and more particularly to an orange tree whichproduces fruit which are mature for harvesting and shipmentapproximately early spring in Kenley, Victoria, Australia and whichfurther is distinguished principally as to novelty by producing largefruit which hang on the tree longer and with a higher internal flesh andexternal rind quality and color than the fruit of the "Late Lane Navel"orange tree.

The development of new varieties of citrus trees has not been asextensive as in the case of other families of fruit trees. In the UnitedStates, for example, while the sweet orange, known botanically as"Citrus sinensis", is typically a greater producer of fresh fruit byvolume than any other fruit tree, the number of different varieties inproduction is significantly less than that of many other families offruit trees. By way of illustration only, in the case of peach trees,the Register of New Fruit and Nut Varities, Second Edition, by Reid M.Brooks and H. P. Olmo, 1972, lists more than seven hundred varieties ofpeach trees in contrast to the just more than fifty varieties of orangetrees. This disparity results, in part, from the susceptibility of manyvarieties of orange trees to diseases which are present in most of thecitrus producing countries of the world. The infectious diseases arecaused by bacteria, fungi and viruses and may, depending upon thespecific type of disease, infect all portions of the trees. Accordingly,developmental work may be limited because of the prospect from expendingenormous effort and time in the development of a new variety onlyultimately to discover its susceptibility to a particular disease whichdestroys any significant commercial value therefor.

In any case, because of the comparative dearth of new varieties oforange trees, the discovery of new varieties having characteristicssuperior to those of known commercial varieties or having desirableripening periods and a commercially acceptable resistance to disease isof event greater significance than in the case of other families offruit trees. Where in addition, for example, the ripening period for anew variety of orange tree offers the prospect of fruit of high qualityor otherwise attractive attributes later in the year than hadtheretofore been available in fruit of an equivalent character, the newvariety is of noteworthy importance. The "Chislett Summer Navel" orangetree is such a variety.

ORIGIN AND ASEXUAL REPRODUCTION OF THE NEW VARIETY

The orange tree of the present invention was discovered in 1986 by theinventor in a cultivated grove of eight year old "Washington Navel"orange trees on the inventor's property at Kenley, Victoria, Australia.The orange tree of the subject invention was believed to be a"Washington Navel" orange tree when planted with the other "WashingtonNavel" orange trees in the grove. However, at the time of the discoveryof the instant variety it appeared to be a whole plant sport. As aconsequence, it can now only be stated that the new variety was a sportof a Citrus sinensis tree of unknown parentage in that the sport wasfrom the portion of the tree which had been produced by grafting unknownbudwood into "Citrange" seedling rootstock and planted in 1979.

The new variety was asexually reproduced in 1987 by the inventor GregoryJohn Kendall Chislett by budding onto Citrange seedling rootstock. Theasexually reproduced trees were retained in the nursery on theinventor's property at Kenley and observed since that time. The inventorhas through such observation confirmed that the distinctivecharacteristics, hereinafter set forth, which caused the parent tree tohave been selected have identically reproduced themselves in theasexually reproduced trees. Budwood of the instant variety was sent tothe University of California, Riverside for testing in May, 1990, but nodata is yet available to compare its characteristics when asexuallyreproduced and grown in the Northern Hemisphere.

SUMMARY OF THE NEW VARIETY

The "Chislett Summer Navel" orange tree is characterized as to noveltyby producing a fruit which hangs on the tree considerably longer andlater than the closest comparative variety, the "Late Lane Navel" orangetree. The new variety possesses a higher internal flesh and externalrind quality and color than "Late Lane Navel" orange tree. The fruitproduced by the "Chislett Summer Navel" orange tree is ripe forharvesting and shipment in September in Kenley, Victoria, Australia, orin other words, approximately early Spring in Australia in the SouthernHemisphere.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawing is a color photograph consisting of two frames,the upper frame showing four fruit of the new variety, the first inbottom plan view showing the navel end portion thereof; the second intop plan view showing the stem end portion thereof, the third in sideelevation; and the fourth sectioned transversely of the longitudinalaxis thereof to show the flesh. The lower frame of the photograph showstypical foliage of the new variety.

DETAILED DESCRIPTION

Referring more specifically to the pomological details of this new anddistinct variety of naval orange tree, the following has been observedunder the ecological conditions prevailing at the field of origin whichis located at Kenley, Victoria, Australia. All major color codedesignations are by reference to the Dictionary of Color, by Maerz andPaul, Second Edition, 1950. A "Hunter Colour Difference Meter" ofGardener Laboratories Inc. was also used where deemed appropriate togive an a/b ratio where "a" is a measure of redness and "b" is a measureof yellowness for quantitative estimation of color development.

TREE

Generally:

Size.--For a ten year old tree, measurements taken from parent tree.Measurements taken from parent tree. Height -- 3.1 meters (122.047inches), diameter -- 2.7 meters (106.299 inches).

Figure.--Normal upright growth. Attitude of branches at full floweringwith no fruit on the tree is spreading. Significantly more vigorous anderect than a "Washington Navel" orange tree and noticeably more vigorousthan a "Late Lane Navel" orange tree.

Productivity.--Good compared to the surrounding "Washington Navel"orange trees in the field of origin with higher yields than "WashingtonNavel" orange tree in the early years after planting due to greater treesize. Approximate yield is 125 Kg of fruit per tree in the case of atwelve year old tree on "Citrange" rootstock.

Trunk:

Size.--Measurements subject to variation due to horticultural practicesincluding pruning. Information gathered from parent tree. Height tofirst branch -- 30.5 cm (12.00 inches). Circumference -- 40.0 cm (15.748inches).

Surface texture.--Smooth bark characteristics normal for navel orangetree.

Color.--Brown (7A8) and light brown (11C2).

Lenticels.--Number -- Approximately 15 per square cm (0.155 squareinch). Size -- Approximately 1.0 mm (0.039 inches) diameter.

Branches:

Generally.--The new variety is a spreading branched variety which ismore erect than the "Late Lane Navel" orange tree and significantly moreerect than the "Washington Navel" orange tree. The height to diameterratio for a three year old tree of the new varieth is 1.26. The heightto diameter ratio of the "Late Lane Navel" orange tree is 1.17. Theheight of the new variety is 2.35 meters as compared to 1.91 meters forthe "Late Lane Navel" orange tree in three year old trees. Branchdensity is somewhat less than in the case of the "Washington Navel"orange tree and thus the new variety is a more open tree and similar inbranch density to the "Late Lane Navel" orange tree.

Size.--Length -- 53.5 cm (21.06 inches); 62.0 cm (24.40 inches); 29.0 cm(11.41 inches). Ancillary branches generally 30 cm (11.81 inches) to 70cm (27.55 inches) long with many sub branches of shorter length leadingto new growth producing fruit and flowers. Diameter -- 21.5 cm (8.46inches); 17.5 cm (6.88 inches); 13.0 cm (5.11 inches).

Surface texture.--Same surface texture as trunk.

Color.--One year or older wood -- Brown (7A8) plus light brown (11C2).Immature branches -- Green (16L1).

Lenticels.--Number -- Approximately 14 per square cm (0.155 squareinch). Size -- Approximately 0.5 mm (0.019 inches) in diameter.

Thorns.--Thorns are present on juvenile and mature wood but are mainlypresent on water shoots. The variety is not considered "thorny" with theextent of thorniness being slightly more than in the case of the"Washington Navel" orange tree and similar to that of the "Late LaneNavel" orange tree.

LEAVES

Generally: Leaves are concave and, undulated, but not excessively so,with medium firmness of leaf blade. Petiole wings are rudimentary indevelopment with a 2.67 mm (0.105 inches) width. This is significantlydifferent (P=0.05) from other late navel varieties except "Late LaneNavel" in 1991. The widths of the petiole wings in other varieties oforange trees were, respectively, as follows: "Powell" orange tree --2.35 mm (0.093 inches); "Barnfield" orange tree -- 2.28 mm (0.090inches); "Rhode" orane tree -- 2.38 mm (0.094 inches); "Summer Gold"orange tree -- 2.99 mm (0.118 inches); "Autumn Gold" orange tree -- 2.37mm (0.093 inches) and "Late Lane Navel" orange tree -- 2.39 mm (0.094inches).

Size:

Generally.--Medium to small. Simple leaves with reticulate veination.

Average length.--Mean approximately 10.95 cm (4.311 inches). Range 9.00cm (3.543 inches) to 15.00 cm (5.905 inches).

Average width.--Mean approximately 5.31 cm (2.090 inches). Range 3.20 cm(1.259 inches) to 6.40 cm (2.519 inches).

Shape: Elliptical.

Base.--Acute.

Apex.--Attenuate.

Color:

Upwardly disposed surface.--Green (22H6). Immature leaves Green (21L7).

Downwardly disposed surface.--Green (21I2). Immature leaves Green(20H3).

Marginal form:

Generally.--Entire to slightly sinuate.

Glandular characteristics: Dotted over underside. Stomata approximately146 per square cm (0.155 square inch).

Petiole:

Length.--Approximately 1.68 cm (0.661 inches). Range 0.70 cm (0.275inches) to 3.4 cm (1.338 inches).

Thickness.--Approximately 3.79 mm (0.149 inches). Range 0.60 mm (0.023inches) to 5.0 mm (0.196 inches).

Stem glands: None observed.

Stipules: None observed.

Leaf aroma: Has a distinctly more volatile and stronger aroma, which is"lemony" in character, in contrast to that of the "Washington Navel"orange tree which is sweeter, while that of the "Late Lane Navel" orangetree is "grassy" in character.

FLOWERS

Flower buds:

Size.--Length approximately 1.46 cm (0.574 inches). Range 1.0 cm (0.393inches) to 1.8 cm (0.708 inches). Diameter approximately 0.25 mm (0.364inches). Range 5.0 mm (0.196 inches) to 12.0 mm (0.472 inches).

Shape.--Elliptical.

Petiole.--Length approximately 7.95 mm (0.312 inches). Range 6.0 mm(0.236 inches) to 10.0 mm (0.393 inches).

Color.--White (9D1).

Flowers:

Date of first bloom.--Oct. 4, 1989 in Kenley, Victoria, Australia.

Size.--Generally -- Same as bud petiole lengths.

Petiole.--Five sided glabrous, corresponding to each sepal.

Petals.--Number -- 5 fleshy, alternate to sepals. Color -- White (9D1).Size -- Approximate length 1.35 cm (0.531 inches). Range 1.0 cm (0.393inches) to 1.54 cm (0.606 inches). Approximate diameter 0.45 cm (0.177inches). Range 0.35 cm (0.137 inches) to 0.50 cm (0.196 inches).

Stamens.--Number -- medium Approximately 25. Range 23 to 28. Style --Development is complete.

Anthers.--Number -- Approximately 25. Range 23 to 27. Color -- Paleyellow (RHS grey-yellow 162A and 162B.

Pistil.--Ovary locule number -- 12 carpellary. Range 10 to 14. Axileplacentation, 1-2 ovules per ovary. Hypogynous receptacle. Disc present.

Pollen.--No viable pollen is present.

Inflorescences: Appear as single terminal flowers and as clusters.

FRUIT

Maturity when described: Ripe for commercial harvesting and shipmentapproximately mid Spring holding until mid Autumn in Kenley, Victoria,Australia in the Southern Hemisphere. Harvest period lastingexceptionally long when compared with other varieties extending fromearly August to the end of April in the following calendar year inKenley, Victoria, Australia. Earliest measurement September, 1988 (15.1sugar/acid ration).

Comparison with other varieties: Large, although smaller than"Washington Navel" orange tree at full color. For example, averagediameter is 73.4 mm (2.89 inches) compared to 76.4 mm (3.01 inches) for"Washington Navel" orange tree in late July. Intrafruit size and shapeuniformity in late July is higher than for "Washington Navel" orangetree. Fruit is of high quality commercial grade of oblate to globoseoverall shape. This compares with the shapes of the fruit of othervarieties of orange trees as follows: "Late Lane Navel" orange tree --globose to ovoid; "Powell" orange tree -- oblate to ovovoid; "Barnfield"orange tree -- oblate to globose; "Rhode" orange tree -- globose toovoid; "Summer Gold" orange tree -- globose to ovoid; and "Autumn Gold"orange tree -- globose to ovoid. Shape of distal end is truncated toslightly nippled with basal end truncate to moderately depressed. Thecolumella is small at 6.5 mm (0.256 inches) average compared to otherlate navel varieties and is semi-hollow to solid in structure. The fruitof the "Late Lane Navel" orange tree is semi-hollow.

Size:

Generally.--Average to good size. Similar to fruit of "Late Lane Navel"orange tree.

Latitudinal fruit diameter.--Approximately 83.18 mm (3.274 inches).Ranging from 70.1 mm (2.759 inches) (early Spring 1989) to 88.5 mm(3.484 inches) (measured Mar. 15, 1989 in Autumn).

Longitudinal fruit diameter.--Approximately 86.96 mm (3.423 inches).Ranging from 72.0 mm (2.834 inches) (early Spring 1989) to 90 mm (3.543inches) (measured Mar. 15, 1989 in Autumn).

Form.--Uniformity -- Good.

Seeds.--None.

    ______________________________________                                        Form-Symmetry-Height to width ratio                                                                Date                                                     ______________________________________                                        1.008                November 4, 1988                                         0.996                December 12, 1988                                        1.012                February 14, 1989                                        1.016                March 15, 1989                                           1.031                April 18, 1989                                           1.024                September 15, 1989                                       ______________________________________                                        Fruit Stem End Depression Height                                                                   Date                                                     ______________________________________                                        2.6 mm (.102 inches) November 4, 1988                                         4.0 mm (.157 inches) December 12, 1988                                        4.5 mm (.177 inches) February 14, 1989                                        4.9 mm (.193 inches) March 15, 1989                                           5.4 mm (.212 inches) April 18, 1989                                           ______________________________________                                        Fruit External Navel Diameter                                                                      Date                                                     ______________________________________                                        5.4 mm (.212 inches) November 4, 1988                                         6.7 mm (.236 inches) December 12, 1988                                        4.5 mm (.177 inches) February 14, 1989                                        5.9 mm (.232 inches) March 15, 1989                                           4.9 mm (.193 inches) April 18, 1989                                           ______________________________________                                        Fruit Individual Mass                                                                              Date                                                     ______________________________________                                        266.7 g (9.33 oz)    November 4, 1988                                         307.9 g (10.77 oz)   December 12, 1988                                        350.8 g (12.27 oz)   February 14, 1989                                        345.8 g (12.10 oz)   March 15, 1989                                           335.8 g (11.75 oz)   April 18, 1989                                           ______________________________________                                    

Stem.--Length -- Approixmately 8.0 mm (0.314 inches). Range 6.8 mm(0.267 inches) to 11.2 mm (0.441 inches). Thickness -- Approximately 3.9mm (0.153 inches). Range 3.1 mm (0.122 inches) to 6.0 mm (0.236 inches).

Skin:

    ______________________________________                                        Thickness - Neck End Rind                                                                        Date                                                       ______________________________________                                        6.0 mm (.236 inches)                                                                             November 4, 1988                                           8.3 mm (.326 inches)                                                                             December 12, 1988                                          8.4 mm (.330 inches)                                                                             February 14, 1989                                          10.7 mm (.421 inches)                                                                            March 15, 1989                                             10.4 mm (.409 inches)                                                                            April 18, 1989                                             ______________________________________                                        Equatorial Rind Thickness                                                                        Date                                                       ______________________________________                                        4.7 mm (.185 inches)                                                                             November 4, 1988                                           5.3 mm (.208 inches)                                                                             December 12, 1988                                          5.8 mm (.228 inches)                                                                             February 14, 1989                                          6.3 mm (.248 inches)                                                                             March 15, 1989                                             5.5 mm (.216 inches)                                                                             April 18, 1989                                             ______________________________________                                        Navel End Rind Thickness                                                                         Date                                                       ______________________________________                                        3.2 mm (.125 inches)                                                                             November 4, 1988                                           3.4 mm (.133 inches)                                                                             December 12, 1988                                          3.9 mm (.153 inches)                                                                             February 14, 1989                                          3.8 mm (.149 inches)                                                                             March 15, 1989                                             3.6 mm (.141 inches)                                                                             April 18, 1989                                             ______________________________________                                    

Rind texture.--Significantly fine and smooth compared to that of the"Washington Navel" orange tree and detectably smoother than that of the"Late Lane Navel" orange tree when compared on the inventor's property.Rind texture can be extremely smooth on the navel end with a high lustregraduating to slightly pebbled at the stem end. Rind texture on a 0 to 5scale where 1=smooth and 5=rough. Average 2.72 smooth compared to thestandards of "Washington Navel" orange tree and "Valencia" orange tree.5 to 7 latitudinal grooves radiating from the neck end.

Rind color.--Color in October is Orange (RHS 24a) and is the same asthat of the "Late Lane Navel" orange tree, being more yellow and lightercolored than that of the "Washington Navel" orange tree. The new varietyattained full orange color approximately four weeks later than that ofthe "Washington Navel" orange tree and at least two weeks after "LateLane Navel" orange tree. Color break is in mid-May with completecoloration occurring by mid-July in North Western Victoria (Kenley,Australia). a.b. ratio -- 0.24 in Autumn in Australia -- Apr. 18, 1989.Orange (10H10) in Spring in Australia -- Oct. 13, 1989.

Handling quality.--Excellent. Skin is hard which makes it excellent forhandling.

Peeling characteristics.--The rind is hard with medium adherence to theflesh which makes it more difficult to peel than the fruit of the"Washington Navel" orange tree and is similar in this respect to that ofthe "Late Lane Navel" orange tree.

Regreening.--Regreening is not severe, but does occur somewhat beginningin December and January varying from year to year and is similar to theregreening of "Valencia" orange tree, although not as severe. "Late LaneNavel" orange trees appear to regreen more than the instant variety.Regreening usually disappears after April. The tendency to maintain anorange color during on-tree storage is greater than other late navalvarieties and is the only late navel to maintain a color more orangethan green (a positive Hunter a/b ratio) throughout two consecutuveseasons. Fruit of the "Washington Navel" orange tree does not store onthe tree long enough to regreen. Rind puffing with on-tree storage isnot excessive and if fruit is not large at maturity resistance topuffing is high. Tendency to puff is less than that of the "Late LaneNavel" orange tree.

Oil glands.--Oil glands are conspicuous with medium density of 40.6glands per 25 mm² compared to "Late Lane Navel" orange tree having 44.4glands per 25 mm².

Navel.--The navel is always present and is always visible, moderatelyprotruding, but not prominant. Diameter is 1.4 mm (0.055 inches) to 17.1mm (0.673 inches).

Albedo.--Color of the albedo is white. Less albedo intrusion betweensegments than in the case of the "Washington Navel" orange tree and"Late Lane Navel" orange tree. The number of segments ranges from 9.0 to12.0 with a mean of 11.2 compared to "Late Lane Navel" orange tree at amean of 10.2. Segment to Segment adhesion is greater than for "Late LaneNavel" orange tree and much greater than for "Washington Navel" orangetree.

    ______________________________________                                        Fruit Softness - Deformation                                                  from 2 Kg force    Date                                                       ______________________________________                                        4.2 mm (.165 inches)                                                                             November 4, 1988                                           3.5 mm (.137 inches)                                                                             December 12, 1988                                          4.9 mm (.192 inches)                                                                             February 14, 1989                                          4.2 mm (.165 inches)                                                                             March 15, 1989                                             5.7 mm (.224 inches)                                                                             April 18, 1989                                             ______________________________________                                    

Flesh color.--Orange (9L9) in Spring of Australia, 1989.

Juice.--The juice content is high and ranged from 51.8% to 55.9% in 1989and juice citric acid content ranged from 0.40 to 0.57 g/100 ml in 1989,decreasing over the season.

Juice flavor.--Very sweet and pleasant and after November does notembitter on storage due to a low limonin concentration. The Sugar toAcid Ratio is high, increasing from 15.1 to 32.6 over the season fromSeptember to March, 1988/89 at Kenley, Australia. The fruit and juice,therefore, tastes less acidic and sweeter as the season progresses, butalways remains attractive. The fruit has no areola and the style is notpersistent. The pulp vesicles are large and long with less randomorientation than in the case of the "Late Lane Navel" orange tree andvery juicy.

    ______________________________________                                        Juice - Percent Juice Content                                                                      Date                                                     ______________________________________                                        55.9 Percent         November 4, 1988                                         55.6 Percent         December 12, 1988                                        52.1 Percent         February 14, 1989                                        51.8 Percent         March 15, 1989                                           51.8 Percent         April 18, 1989                                           ______________________________________                                        Juice - Citric Acid Content                                                   in Grams per 100 Millimeters:                                                                      Date                                                     ______________________________________                                        0.57 (g/100 ml)      November 4, 1988                                         0.50 (g/100 ml)      December 12, 1988                                        0.37 (g/100 ml)      February 14, 1989                                        0.35 (g/100 ml)      March 15, 1989                                           0.40 (g/100 ml)      April 18, 1989                                           ______________________________________                                        Juice - Sugar Content in Degrees Brix:                                                             Date                                                     ______________________________________                                        13.1                 November 14, 1988                                        12.2                 December 12, 1988                                        11.2                 February 14, 1989                                        11.4                 March 15, 1989                                           11.4                 April 18, 1989                                           ______________________________________                                        Juice - Sugar to Acid Ratio:                                                                       Date                                                     ______________________________________                                        15.1                 September 16, 1988                                       19.4                 October 11, 1988                                         23.0                 November 4, 1988                                         24.4                 December 12, 1988                                        30.3                 February 14, 1989                                        32.6                 March 15, 1989                                           28.5                 April 18, 1989                                           ______________________________________                                        Total Soluble Solids in                                                       Kilograms per Metric Ton:                                                                          Date                                                     ______________________________________                                        73.8 Kg/tonne        November 4, 1988                                         68.4 Kg/tonne        December 12, 1988                                        58.7 Kg/tonne        February 14, 1989                                        59.4 Kg/tonne        March 15, 1989                                           59.5 Kg/tonne        April 18, 1989                                           ______________________________________                                         (Tonne: a Metric Ton: 1,000 Kilograms)                                   

Flavor.--No off flavors were detected. Non limonin bitter taste wasdetected.

Aroma.--Noteworthy.

Ripening.--Even and very late.

Eating quality.--Very noteworthy.

Resistance to fruit drop.--Considered high for a late navel variety.Although slight fruit drop can occur beginning in late November, most ofthis is due to slight splitting from the navel or some other damage.Approximately 70% of fruit remains on the tree until April, seven monthsafter maturity. A significant amount of fruit can hang for more thantwelve months after maturity, as will fruit of "Valencia" orange trees,although resistance to drop is not as high as for "Valencia" orangetrees. The resistance to fruit drop of the instant variety is higherthan in the case of the "Late Lane Navel" orange tree as most will nothang after the end of November. "Summer Gold" orange trees fall heavilyby November in North Western Victoria, Australia.

Although the new variety of navel orange tree possesses the describedcharacteristics noted above as a result of the growing conditionsprevailing in Kenley, Victoria, Australia it is to be understood thatvariations of the usual magnitude and characteristics incident tochanges in growing conditions, fertilization, pruning, pest control andother horticultural practices are to be expected.

Having thus described and illustrated my new variety of navel orangetree, what I claim as new and desire to be secured by Plant LettersPatent is:
 1. A new and distinct variety of navel orange treesubstantially as illustrated and described and which is somewhatremotely similar to the "Late Lane Navel" orange tree with which it ismost closely similar, but from which is distinguished and characterizedprincipally as to novelty by producing fruit which are mature forcommercial harvesting and shipment in early September and which holds onthe tree until the end of April of the following year in Kenley,Victoria, Australia and which possesses a higher internal flesh andexternal rind quality and color than comparable varieties.